1. Field of the Invention
This invention relates to an edge-cladding glass for a disc laser glass. More particularly, it relates to an edge-cladding glass for a disc laser glass, which has a low fusion temperature, a high thermal expansion coefficient and a high absorption coefficient in the vicinity of the central wavelength of laser light.
2. Description of the Prior Art
It is known that when spontaneous emission light generated in a disc laser glass in which energy has been accumulated by the pumping of a Xe flash lamp is reflected and scattered at disc edges and amplified such that the gain exceeds the loss; oscillation, known as parasitic oscillation, occurs. When oscillation occurs, the energy accumulated is consumed instantaneously. This phenomenon can be prevented by surrounding the circumferencial portion of the disc with a medium having reduced reflection and scattering and capable of absorbing the laser light (e.g., the glass of this invention) so that the spontaneous emission light cannot be reflected and scattered at disc edges. This contrivance is known in the art as "edge cladding" and is discribed in U.S. Pat. Nos. 3,885,974 and 3,966,448.
A general method of edge-cladding comprises mixing a low fusion temperature glass powder with a dispersing agent to form a slurry, coating the slurry on the edge of the disc laser glass, and heat-treating the coated glass at a temperature below the temperature at which the disc glass is softened and deformed, to thereby melt-bond the low fusion temperature glass to the edge of the disc glass. This method tends to leave a number of bubbles in the clad glass, which increase considerably the reflection and scattering of spontaneous emission light.